The heat-shocking resistance of SiC(w)/ZrO2-MoSi2 ceramic composites prepared by hot-pressing sintering was studied by indentation-quench method together with the calculation of the crack propagation rate of ceramic nanocomposites. The results showed that the crack propagation rate of MoSi2 matrix ceramics samples decreased remarkably with the addition of ZrO2 and SiC nanoparticles. The crack propagation rate of SiC(w)/ZrO2-MoSi2 ceramic composites was obviously lower than that of ZrO2-MoSi2 ceramic composites, which revealed that the synergism between SiC(w) and ZrO2 was more advantageous to enhance the heat-shocking resistance of MoSi2 ceramic. Moreover, the ability of ZrO2 particles to hinder the heat-shocking crack propagation was better than that of SiC whiskers. The synergism between SiC(w) and ZrO2 changed the crack propagation path and shape in MoSi2 ceramics. The mechanisms of ZrO2 to improve the heat-shocking resistance of the MoSi2 ceramic were mainly phase transfer toughening, while that of SiC whiskers to improve the heat-shocking resistance of the MoSi2 ceramic were mainly crack deflection and bridge union.